Thursday afternoon, half past three. A work planner opens the folder of a new order: an assembly, a stack of PDFs and a bill of materials. Within ten minutes, four questions go out to engineering: which revision is this, is Tuesday's customer change already included, is item 14 a purchased part or a manufactured part, and where is the drawing of the tube frame? Engineering has moved on to the next project, so the answers trickle in. Meanwhile, the order sits still.
Those questions are not a sign of unwillingness or sloppy work. They are the result of a missing agreement: what exactly does engineering hand over, in what form, and what does "done" mean? In this article we turn the engineering handover to work preparation into an agreement instead of a guess. We cover what belongs in the handover package, how to pin down when something is ready to hand over, and how to prevent the questions work planners otherwise ask on every single order. A toolbox like Thundercad makes the package reproducible, but the agreement itself comes first.
Noise is the gap between two definitions of done
For engineering, an order is done when the model is correct and the last drawing has been released. For work preparation, the work only starts there: ordering material, planning operations, requesting outsourced work, preparing cutting lists. Between those two worlds sits a handover moment that hardly anyone has ever made agreements about. Engineering delivers what it always delivers, work preparation gathers what it needs, and the difference is fought out over email.
That noise feels like a series of small annoyances, but do the math. Assume four questions per order, fifteen minutes of searching and answering per question, and an average of an hour of waiting for each answer. Those are assumptions, so measure a week in your own inbox, but at ten orders a month you quickly lose a full day to searching and waiting. And every interruption is a moment where someone assumes instead of knows.
What belongs in the handover package
The test for a complete package is simple: work preparation can move forward without having to ask engineering anything. In practice, that means at least this:
- The BOM, refreshed after the last model change, with quantities, units and the make-or-buy distinction for every item.
- Drawings of every manufactured part and assembly the shop floor or a supplier needs.
- The metadata work preparation builds on: order number, project number, material, revision and status. Not in someone's head, but in the files and in the columns of the list.
- For a revision: one change line. What differs from the previous release, and which items it affects.
- One sender and one moment: who handed this over, and when.
What each recipient needs exactly differs per company; how to compose that full package and who gets what is covered in The complete production package: what do you deliver, and to whom?. For the handover itself, predictability matters most: the same package, the same layout, every single time.
Agree on what "done" means
The word "done" is the biggest source of noise, because everyone reads something different into it. Turn it into a short list of hard criteria, drawn up together with work preparation:
- Every manufactured item has a drawing, and every drawing belongs to an item in the BOM.
- The BOM was refreshed after the last model change, not before it.
- The agreed metadata is filled in; an empty field blocks the handover and is not a detail.
- The revision has been raised and the change is described in a single line.
- The model contains no loose ends: no suppressed components that still need to return, no forgotten test geometry.
How you draw up the list matters more than its exact content: engineering only knows what "done" should mean once work preparation explains what it gets stuck on every week. One meeting of an hour usually produces a workable first version.
A consistent handover package does not have to be manual work: with Thundercad you export drawings and the BOM to the same folder structure in a few clicks, order after order.
Try 30 days freeThe questions work planners ask most often
Ask a work planner which questions come back every week and you will hear almost the same list everywhere. Each of them can be prevented up front; that is exactly what the package is for.
"Which revision is this, and does it include the latest change?" Prevent it: revision and release moment are in the list and on every drawing, and the package is only handed over after the last change. Sending half a package early "so they can get started" creates more work than it saves.
"Is item 14 a purchased part or a manufactured part?" Prevent it: that distinction is a field in the BOM, filled from the model. It must never be a knowledge question for the engineer, because then it gets asked again on every order.
"Where is the drawing of the tube frame?" Prevent it: all exports land in one fixed folder structure, identical for every order. With Export Folder that happens automatically: drawings and lists always end up in the same place, and a missing drawing stands out as a gap in a row instead of a surprise three days later.
"Is this the final list?" Prevent it: there is only one release path. The list comes straight from the model with Export BOM, in a fixed template with fixed columns, and sits in one agreed place. As soon as two lists circulate, someone is guaranteed to work from the wrong one.
"What changed compared to the previous version?" Prevent it: the change line in the package. Not every change deserves a story; "bracket item 8 dropped, plate item 12 now 6 millimetres" is enough to check the right spots.
The handover as a fixed routine
With an agreed package and an agreed definition of done, the handover itself becomes small: export to the fixed structure, walk through the checklist, send a short message to work preparation with the order number. Ten minutes, the same every time. The gain is not in those ten minutes but in everything that no longer happens afterwards: no rounds of questions, no second list in circulation, no purchasing that starts from an outdated revision.
The content quality of the BOM itself is a separate discipline: quantities, duplicates, units. We covered that earlier in Five BOM errors that only show up on the shop floor. The handover agreement does not fix those errors, but it does make sure they are found in a complete, current package instead of in three scattered emails next to the truth.
Frequently asked questions
Who owns the handover: engineering or work preparation?
Engineering delivers, so engineering hands over. But you draw up the definition of "done" together, and work preparation helps decide what goes into the package: they are the internal customer of this delivery. A handover designed by one side only will keep raising questions.
What if the package is incomplete: send it back or fix it yourself?
Send it back, however unfriendly it feels. Every time work preparation fills the gaps itself, the incentive to get the package right disappears and knowledge starts living outside the model. Rush jobs happen, but do not let the exception become the standard route.
How much time does a fixed handover cost per order?
Count on about ten minutes for exporting, the checklist and the message, assuming the model and drawings are in order. The exporting itself takes a few clicks with Export Folder and Export BOM. If you want to try that on your own orders, you can try Thundercad free for 30 days.